Field of Invention
The present invention relates to the manufacturing filed of tobacco, and particularly to a forming method and a forming device for a cigarette filter.
Description of Related Arts
In order to filter some certain of hazardous substances (such as nicotine, tar) of cigarette smoke, the vast majority of current cigarettes are provided with filter rods. The filter rod is produced by a filter rod forming machine, e.g., the KDF2 filter rod forming machine produced by Hauni Company, Germany. The machine generally consists of two parts of a tow pretreatment section (AF) and a filter rod forming section (KDF), the coming cellulose acetate tows are the continuous fiber tows having been compressed and packaged, then the fiber tows is continuously fed into the machine; during the tow pretreatment process, the cellulose acetate tows are opened and expanded to a relative loose and board fiber band, which is sprayed with plasticizer later. By the filter rod forming section, the loose, glued fiber band is furled to a carton though a furled device with a taper horn mouth, and then is packed with a continuous filter rod prepared by a forming paper. Next, after being cut into particular length specifications by a rotary cutter, the formed cellulose acetate is shaped and solidified under the action of plasticizer, and becomes a stable shaped filter rod.
A key direction of the development of cigarette manufacturing process, is to study how to reduce the harm of the hazardous substances, that are generated from the lighting and smoking of a cigarette, to human body. At present, one method commonly used is that, by applying granular additives with different absorption effects and functions, such as active carbon granules, molecular sieve granules and the like, so as to improve the filtration effect of the filter rod on hazardous substances. Besides, in order to allow smokers to get a different consumer experience, the filter rod inside is usually added with microcapsule granules containing liquid perfumes of a floral perfume, peppermint and the like, so that smokers is supplied with changes of fragrance and sensory effects. Generally, a special functional filter rob with granular additives is produced by the existing device of filter rod of cellulose acetate, by adding a particular apparatus of granular additives. In the existing technology, an apparatus of granular additives is widely arranged between a tow pretreatment section and a filter rod forming section, and then the granular additives are released to continuous transporting fiber bands; after the filter rod forming part is furled, the additives is tightly wrapped and fixed therein, so that the addition of additives is achieved.
Publication Number: WO2006/059134, title: Tobacco smoke filter production, Filtrona international limited, Milton Keyence, UK, has disclosed a production method for a filter rod with granular additives, in which the granular additives is discontinuously supplied into a pneumatic injector conduit by a valve. The valve is opened and closed repeatedly, to allow the injector conduit for feedstock and spray in a pulse mode, so that the granular additives is laterally spray to a center of collected filter material conveying forward. In such production method, the granular additives are sprayed to the filter material by adopting pulse flows, while pulse flows are discontinuous, and it requires for duty time between two sprays, which makes it difficult to carry out high-speed production. The pulse flow is varied periodically with strong and weak, which will affect the stability of the shaped granular additives.
Publication Number: WO2006/067629, title: Compound filter rod making apparatus and process, Philip Morris products S.A., Neuchatel, CH, has disclosed an apparatus for continuously making compound filter rod, in which a rotary pocket wheel is adopted. The wheel is provided with a number of interval cells, and a vacuum source applying to the rotary wheel is adopted to absorb filter mediums (granular additives) from a filter medium supply to the cell. The rotary wheel rotates upwards to a transfer opening, to release vacuum; compressed air is applied to a perforated pocket “bottom” to convey the filter mediums to a shaped continuous filter rob center, to achieve the release of granular additives. The device absorbs feedstock by vacuum, thus granular additives are likely to block the vacuum system that leads to shortage of material; besides, reliability of feedstock is reduced during high-speed operation, thereby causing shortage of material. It improves the difficulty of machining when adopting matched sealing surfaces to form a pressure system, and granular additives directly touch with the sealing surfaces, which is likely to cause pressure sealing failure.
Moreover, the above two devices for forming filter rob feature a common shortcomings, that is, during the process of forming filter rob, it is generally added with just one type of granular additive, thus, the produced filter rob contains one type of granular additive as well, in such way, the function of a cigarette filter rod is limited.